In many vehicles, a floor console (an example of the installable component) is disposed along with a vehicle seat in consideration of convenience to occupants or the like. For example, in a vehicle disclosed in JP-A-H9-277878, a floor console is disposed between a driver seat and a passenger seat which are vehicle seats. Each of the driver seat and the passenger seat as vehicle seats includes a seat cushion and a seat back rising upward from the seat cushion. The floor console is a cubic box member which is formed by injection-molding an appropriate resin material and plural engaging protrusions are formed on the bottom end thereof. In the related art, a resin floor-shaping member is disposed on a vehicle floor surface and locking holes into which the engaging protrusions can be fitted are formed in the floor-shaping member. By inserting and fitting the engaging protrusions into the locking holes in the vertical direction, the floor console can be disposed on the vehicle floor surface between the driver seat and the passenger seat.
In the above-mentioned configuration, for example, in consideration of the shape or size of the vehicle seat or the like, a hole-shaped or cutout-shaped accommodating section in which the floor console is arranged may be provided in the seat back. The floor console is disposed in the accommodating section and the vehicle seat and the floor console are fixed to the vehicle floor surface. In this state, in consideration of appearance or the like, it is preferable that the floor console is disposed with an appropriate posture at an appropriate place in the accommodating section. However, in the related art, the floor console is fixed to only the vehicle floor surface. Accordingly, for example, when the positional relationship between the vehicle floor surface and the accommodating section varies, the floor console may not be appropriately disposed in the accommodating section.